I. Technical Field of the Invention
This invention relates generally to communications networks and, more particularly, to a system and method for establishing a reliable communications link between a personal computer or workstation and such networks.
II. Description of the Related Art
Network interface cards (NIC) are widely used for connecting computer devices to a data network to facilitate the exchange of data therebetween. Most data networks provide for bi-directional data transmission wherein data is transmitted in an upstream direction from a computer to the network where the data is received by a receiving device also connected to the network, and in a downstream direction wherein data is received from the network by a destination device, e.g. a personal computer or the like. As is widely known, such networks require that the data signals carried thereby adhere to a specific data format or protocol recognized by the network. Thus, existing NICs convert upstream computer data to the appropriate protocol for the network before the data is transmitted. Likewise, conversion of the downstream data from the network protocol to a format recognized by the destination computer device is performed by the NIC.
Most computers provide I/O ports for controlling various peripherals. While such peripherals typically include printers, they may also include non-computer or telecommunications terminal devices, such as analog or digital telephones, videophones, facsimile machines, answering machines, computer data and/or fax modems, and adjunct devices such as caller-ID, which communicate with like devices on a telephone communications network that is separate from the computer data network. In addition, internet "telephones" now exist in the form of software that allows a user to speak into a handset, for example, which is connected to a sound card in a CPU of a computer for transmission of the spoken data on or over the data network or internet. While such a configuration allows the internet telephone to transmit data through the computer data network, the dependency of such devices on the CPU creates several drawbacks. For example, if the CPU is engaged in other operations or calculations during the use of the internet telephone, the perceived quality of the telephone call may decrease. During use of the internet telephone, conversely, fewer processing resources of the CPU are made available to other applications.
As will be readily appreciated by those skilled in the art, interruptions in the operation of the computer or workstation are inevitable. These may result, for example, from power disruptions, software operating system faults (i.e. "hanging") or hardware failures such as, for example, hard drive failures or memory errors, system resets and reboots initiated by the user. Where the network connection to the telephonic device depends upon the processing and power resources of the personal computer or workstation, any of the aforementioned interruptions will disrupt the flow of data between the telecommunications terminal and the computer network.
Accordingly, there exists a need for a network interface card or adjunct module which can reliably allow at least one telecommunications terminal to interact, via a single connection, with a common network that carries both computer data and telecommunications traffic.